What is the threshold (nisab) and the amount of zakat due upon the owner of a small computer company who works in a rented place, and owns computers and furniture upon which a full year has passed?

Zakat is obligatory on equipment and furniture if they were purchased with the intention of sale, once their value reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over them, whether by themselves or when combined with money and other trade goods. However, if they are intended for rent or personal use, Zakat is not obligatory on them. But the income derived from their rent is subject to Zakat once it reaches the nisab and a hawl passes over it, according to the aforementioned conditions.